In the prior art, the synthetic jet device includes a central chamber where a central nozzle is disposed on the upper side thereof and a driving device is disposed at the bottom side thereof used for driving one side of the chamber to have a reciprocating motion in order to vary the volume of the chamber so that the volume of the chamber would be shrunken and expended over and over again like a piston, whereby the fluid filled inside the chamber could be pumped out of the chamber to an outer space or be injected from the outer space to the chamber. In the forward stroke the fluid in the chamber will flow through the central nozzle to form a high velocity jet flow, and in the backward stroke the fluid around the central nozzle will be injected into the chamber. Through such reciprocating motion with the forward and backward strokes, a jet flow flowing toward a specific direction is therefore formed. The aforementioned conventional device is characterized in that: the mass flux passing through the cross-section of the central nozzle is zero, that is, the flux is a zero-net-mass-flux. Currently, the applied field of the synthetic jet device are mainly focused on the following three aspects: (1) the flow field control; (2) the mixture and the combustion of the condensed fuel; and (3) heat diffusion system.
Typically, the research regarding how to apply the synthetic jet into the technical field of the flow field control has been widely studied. Earlier to B.C. 1950, there were scholars who had carried out the relevant research, for instance, Perkins and Hazen (1953) who proceeded a study with respect to actively adjust the pressure distribution on the surface of an aerodynamic apparatus in order to improve the aerodynamic performance thereof. In recent years, Rathnasingham (1997) etc. and Rediniotis (1999) etc. also proceed the relevant research to the aforementioned field. Besides, in B.C. 2000, Honohan etc. proceed an experiment to further observe the flow field pattern that an uniform flow passes through a cylinder from the surface of which a synthetic jet is provided. In this research, it is proved that a synthetic jet could efficiently suppress the incensement of the boundary layer along the object surface, which cause the flow field able to resist a more adverse pressure gradient, so as to postpone the generation of the separation flow. Further, such as: Kral etc. (1997), Smith etc. (1998) and Amitay etc. (1999, 2001) utilize the synthetic jet flow to control the lift force and resistance of an aerofoil. Lorkowski etc. (1997) utilize the synthetic jet flow to reduce the surface friction force inside the flat boundary layer. Amitay etc. (2001) utilize this mechanism to control the separation phenomenon for the pipe flow.
The research that apply the synthetic jet flow into the mixture and the combustion of the condensed fuel are mainly focused on how to well blend the fuel and the oxidant by using the synthetic jet flow, in order to provide a combustion status that a fuel-rich and a fuel-lean are alternatively formed. This is the very famous and potential low NOx combustion technique.
In recent years, applying the synthetic jet flow into the cooling system is a newly raising research field. Its application is mainly focused on the packaging process for micro-electro-mechanical-system to improve the efficiency of the heat management. For instance, Glezer and Mahalingam (2002, 2004) integrally utilize the synthetic jet flow to guide the working fluid containing the wasting heat to the cooling fan. The relevant experiment proves that although the mass of the driven fluid in this method is 70% lesser than that of the conventional method, the cooling efficiency is improved approximate up to two or three multiple times. It reveals that the synthetic jet flow possesses the great potential to be applied into this field. Besides, Smith and Beratlis (2003) publish a studying result regarding a series of efforts trying to find out an optimized application of the synthetic jet flow while using in a cooling system. Their research aims to utilize an numerical model to design a best cooling performance by controlling the phase angle, the distance between the nozzle and the heat source and the size of the nozzle etc for the synthetic jet flow applied in a VCSEL (Vertical Cavity Surface Emitting Laser) array. The optimized result demonstrates that a cooling efficiency could be up to 132.2 W/m for the VCSEL array. The research also found that under a certain given vibrated amplitude for the piston apparatus, the heat transfer effect is in a nearly positive correlation with the vibrated frequency. Furthermore, Kercher and Glezer etc. (2003) designed a micro jet cooling element whose vibration of the thin film is driven by utilizing the magnetic force so as to produce a synthetic jet flow to achieve the cooling effect. In the this study, it also compares the result of his research with the conventional cooling fan and compared result reveals that the synthetic jet cooling device performs better than that of the conventional cooling fan.
To sum up, since almost the various synthetic jet flow device provide merely the zero-net-mass-flux flow, the defects such as insufficient discharge, low replacement rate, and bad cooling performance commonly exist in these conventional schemes. Hence, the performance of these conventional schemes did have to be well improved.
To overcome the mentioned drawbacks of the prior art, a jet device is provided.